The present invention relates to the formation of stable, aqueous compositions containing a substantially crosslinked alkali-swellable acrylate copolymer rheology modifier, a surfactant, an alkaline material, and various compounds therein, as for example substantially insoluble materials requiring suspension or stabilization, such as a silicone, an oily material, or a pearlescent material. Additionally, this invention also relates to the formation of a rheologically and phase stable cationic hair dye composition. The invention further relates to the incorporation of an acidic material after the addition of an alkaline material to reduce the pH of the composition without negatively impacting the viscosity and rheology of the composition.
Heretofore, various substantially insoluble compounds could not be adequately stabilized in an aqueous surfactant containing composition. For example, various aqueous surfactant compositions which contain silicone additives therein, as for example hair or skin conditioners, would separate and/or cream from their surfactant base. Various pearlescent materials, which are often utilized to provide a pearlescent appearance, would have a short shelf life and produce a diminished pearlescent appearance (xe2x80x9cflatten outxe2x80x9d) or actually settle. In other words, instability problems generally existed with regards to the incorporation of silicones and pearlescent materials.
While cationic or basic dyes for hair have been utilized in shampoos to impart temporary color or highlights, the cationic dyes were generally incompatible with the anionic surfactants typically used in traditional shampoo formulas. Accordingly, amphoteric surfactants have been utilized to impart cleansing and detergency properties to the shampoos, but such surfactants do not sufficiently thicken to provide the desired product rheology. While traditional polymeric rheology modifiers, such as carbomers and/or acrylates/C10-30 alkyl acrylate cross polymers, have been utilized to increase viscosity, the Theological stability of these compositions is still generally poor.
Various attempts have been made to remedy the above problems.
For example, U.S. Pat. No. 5,656,257 relates to an anionic shampoo and conditioning composition comprising an oily conditioning agent, a shampooing agent, an acrylate copolymer, a cationic conditioning agent, and water. It also relates to the incorporation of a C8-C18 fatty acid. The composition utilizes both oily and cationic conditioning agents in combination with an anionic acrylate copolymer for maintaining stability and dispersion.
WO 99/21 530 relates to a hair care composition comprising from about 1.00% to about 80.00% by weight of one or more surfactants selected from the group consisting of anionic, nonionic, cationic and zwitterionic surfactants and mixtures thereof; from about 0.05% to about 15.00% by weight of at least one fatty alcohol having from 10 to about 30 carbon atoms; from about 0.10% to about 15.00% by weight of a non-volatile silicone; and from about 1.35% to about 2.70% by weight of a non-crosslinked polymeric suspending agent.
EPO 463,780 relates to a stable, pearly shampoo composition comprising insoluble, non-volatile silicone which may be obtained by including a suspending polymer, to prevent the silicone xe2x80x9ccreamingxe2x80x9d to the top of the bottle in storage, and also to prevent the particles of titanium dioxide coated mica from settling. The composition further relates to an aqueous shampoo composition comprising in addition to water:
(a) from 2 to 40% by weight of a surfactant chosen from anionic, nonionic or amphoteric surfactants, or mixtures thereof;
(b) from 0.01 to 10% by weight of an insoluble, non-volatile silicone;
(c) from 0.1 to 5% by weight of a suspending polymer chosen from polyacrylic acid, cross-linked polymers of acrylic acid, copolymers of acrylic acid with a hydrophobic monomer, copolymers of carboxylic acid-containing monomers and acrylic esters, cross-linked copolymers of acrylic acid and acrylate esters, and heteropolysaccharide gums; and
(d) from 0.01 to 5% by weight of titanium dioxide coated mica.
U.S. Pat. No. No. 4,529,773 relates to compositions containing an associative thickener (a hydrophobically modified alkali-soluble emulsion polymer) that has been activated by neutralization to a pH above 6.5, and subsequently acidified in the presence of a surfactant.
However, the above prior art does not produce sufficiently stabilized aqueous surfactant compositions such as with respect to various silicones, oily materials, pearlescent materials, cationic hair dyes, and other substantially insoluble materials.
A stable aqueous composition comprises a substantially crosslinked alkali-swellable acrylate copolymer rheology modifier, water, an alkaline material, and an effective amount of a surfactant so that a substantially insoluble compound is stabilized or suspended in the composition. Compositions can be stabilized that contain various volatile and nonvolatile silicone oils, oily materials, and the like. Compositions containing a pearlescent material can be stabilized and which further impart an enhanced pearlescent appearance to the composition. Additionally, compositions containing cationic dyes can be attained and maintained with acceptable rheology. Furthermore, a xe2x80x9cBack-Acidxe2x80x9d formulation technique can be utilized to achieve low pH compositions. These stable aqueous surfactant compositions can generally maintain a smooth, acceptable rheology, without significant increases or decreases in viscosity or pH, with no separation, settling, or creaming out, over extended periods of time such as for at least one month at 45xc2x0 C. The polymeric rheology modifier is generally made from one or more carboxylic acid monomers, vinyl monomers, and polyunsaturated monomers. The surfactant can be an anionic, an amphoteric, a zwitterionic, a nonionic, or a cationic surfactant, or combinations thereof.